BOULDER — Eric Larsen wasn’t sure how long he and partner Ryan Waters had been inching across the frozen wasteland toward the North Pole. Forty-four, maybe 45 days.

“They all blend together, man,” Larsen recalled.

The Boulder adventurers were hauling two sleds, each laden with 320 pounds of food and supplies. They donned dry suits to swim across frigid open water between shifting islands of ice. Polar bears stalked them. They would traverse a mere mile in 12 hours on drifting ice that actually moved them south faster than they could travel north. The plane was coming to pick them up soon — a $100,000 ride. They needed to move faster. Pressure was building, optimism waning.

Larsen sounded dejected in his late April satellite phone update, telling followers to “take the hardest thing you can possibly imagine and do that for 40 days, then make it twice as hard and keep going.”

Three months later, the 43-year-old father of a toddler is still recovering — mentally and physically — from his third 500-mile trip to the North Pole, a land-to-pole expedition completed by fewer than 50 people. Larsen feels his expedition will be the last ever to the North Pole because of shifting, melting ice, changing climate and mounting logistical challenges.

There are many reasons no one has successfully completed a self-supported land-to-pole expedition to the North Pole since Larsen did it last in 2010. First and foremost: It’s monumentally grueling.

“I tell people I cry my way to the North Pole,” said Larsen, describing a monotonous grind that saps spirit and body. “It’s such a struggle with optimism. It’s one of the most difficult expeditions on the planet that no one knows about.”

It’s easy to conjure up the question: “Why?”

Larsen admits he asked himself that question repeatedly during his 53-day slog from Canada’s northern Ellesmere Island to the geographic North Pole. His motivation stems from exposing the unknown.

“My big mission is to connect people to places,” said Larsen, who captured images and video for an upcoming “Animal Planet” documentary produced by Denver’s High Noon Entertainment. “Very few people know about (the North Pole), and very few people understand it. For me, this was about telling a story about a place before it’s gone. I almost feel like we were on this expedition to document an endangered species. This expedition to the North Pole could be the last of its kind, so taking pictures and filming … They are like museum specimens that we are cataloguing.”

The mission was much harder than Larsen’s previous trips in 2006 and 2010. Thirty years ago, polar explorers enjoyed miles of smooth ice sheets and navigated short stretches of giant blocks where those sheets collided. This year, the ice was thinner. There was much more water to swim across. The ice was rough, and there were no long hours of smooth glissading. Larsen estimated he and Waters spent days moving at half a mile per hour, which forced them to work more and sleep less.

Smaller window for travel

Changing ice conditions and shifting weather patterns have made the logistics of polar travel more challenging than ever. The flight window for pick-up at the North Pole is now early May, versus mid-May a couple of years ago. The season for a base camp on the northernmost coast of Canada, a common starting point for most North Pole expeditions, is shorter than ever before. That means adventurers have a smaller window to make the nearly 500-mile traverse. (And speed is hampered with thinning ice and more water crossings.) Add in the astronomical cost of airplane evacuation — at least $100,000 but up to $250,000 for larger parties — and the chances for success dwindle on a mission that rarely succeeds.

“It is becoming more difficult for a number of reasons,” said Annie Aggens, the director of Polar Explorers, which has been organizing polar expeditions since 1993.

Aggens said the growing thirst for adventure probably will push more explorers toward the North Pole, despite Larsen’s dire predictions.

“It is a pinnacle. I will continue to receive e-mails about the North Pole expedition even if no one is successful for the next five years,” Aggens said. “The information we send out pretty much says if you want to do this expedition, think again. This is reserved for people with significant previous experience and fully understand what they are getting involved in, and even those guys have a high rate of failure. It is the hardest expedition on the planet, hands down.”

This year three other parties vied for the North Pole — a self-supported Norwegian team, a supported Irish team and a solo Japanese explorer who moved too slow and ran out of food. Larsen and Waters found the Japanese man huddling in his tent awaiting evacuation.

Larsen said he and Waters skied away from the man feeling “incredibly jealous” that he was done and going home.Familiar with suffering

Larsen and Waters — a professional guide whose return from the Great North was long enough to pack for the climbing season on Alaska’s Denali — are no strangers to suffering. Waters and a partner skied more than 1,100 self-supported miles in 72 days across Antarctica via the South Pole in 2010. Larsen in 2012 was thwarted after 16 days on an attempt to pedal his fat-tired bike to the South Pole, making it almost 200 miles. In 2009 the Wisconsin native began a world-record 365-day push to reach both poles and the summit of Mount Everest, a triple-play feat completed by fewer than 20 people.

Early in the trip, when they were hauling one sled at a time, they turned around to see a mother polar bear and her yearling following in their tracks. There are a lot of components in the formula of a success, Larsen said, such as dedication, expertise and hard work.

But luck plays a big role, too. Luck was on his side when those bears came hunting.

Larsen was warm from hauling, so his fingers worked well enough to assemble the flares in his pockets. But the bears kept marching toward them, despite the flares. They had chosen Larsen’s sled to haul first, and it had the gun. The cracker shells persuaded the bears to turn away.

“If it had been Ryan’s sled …” said Larsen, shaking his head. “Turns out they had been following our tracks for 200, 300 yards. We didn’t even know they were there. That was just pure luck.”

For so many reasons, the 2014 North Pole mission ranks as the most difficult expedition ever, Larsen said.

“Personally, I would have given up if it wasn’t for Ryan,” Larsen said. “If he would have said, ‘You know what: I’m not feeling this,’ I would have said, ‘We are out.’ What do I have to gain for being here again?’ “

Those nagging doubts persist through every expedition. It’s part of the quest, suppressing urges to quit. For Larsen, burying doubt becomes easier when the mission is bigger than himself.

“This expedition is a good platform to talk about important things, and we all need to be reminded that the world is an amazing place and we all have the ability to go out and discover it on whatever level we choose,” he said. “We just need to do it.”

Jason Blevins covers tourism, mountain business, skiing and outdoor adventure sports for both the business and sports sections at The Denver Post, which he joined in 1997. He skis, pedals, paddles and occasionally boogies in the hills and is just as inspired by the lively entrepreneurial spirit that permeates Colorado's high country communities as he is by the views.

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